gistfile1.js

function points_on_a_line( from, to, gap ) {
  // work out the difference in X and Y, and the hypotenuse
  var dx = to.x - from.x,
      dy = to.y - from.y,
      h = Math.sqrt( dx*dx + dy*dy )
      points = [],
      // work out what proportion of the hypotenuse each step will be
      step = gap / h,
      d = 0,
      i = 0;

  // for each step, add that proportion of dx and dy to the start position
  while ( ( d += ( ++i * step ) ) < 1 ) {
    points.push( {
      x : from.x + d * dx,
      y : from.y + d * dy
    } );
  }

  return points;
}

    def each_point(start, finish, max_step)
      dx = finish[0] - start[0]
      dy = finish[1] - start[1]
      hypotenuse = Math.sqrt(dx*dx + dy*dy)
      step = max_step / hypotenuse
      steps = hypotenuse / max_step

      1.upto(steps) do |i|
        yield start[0] + i * step * dx, start[1] + i * step * dy
      end
    end